I think your right. I added prime and H2O2. To the water when I filled tank. And added carbon yesterday to rid any contaminates. No invert or fish were affected and only 2 corals out of 20.

I hope to see stable conditions I guess I may see a mini cycle. Last time I upgraded I never had any issues. But maybe I never paid enough attn as I had mostly Lps then

came home to see my tank is going through its mini cycle glass was gross. cleaned added new skimmer and small water change..

should be good from here on out